Inclusion complexation of isoprenaline and methyl dopa with α- and β-cyclodextrin nanocavities: Spectral and theoretical study

Inclusion complex formation of isoprenaline (ISOP) and methyldopa (MDOP) with alpha-CD and beta-CD were investigated. Solid inclusion complex nanomaterials were characterized by SEM, TEM, FTIR, DSC, H-1 NMR and XRD methods. Spectral results showed that single emission (monomer) noticed in aqueous solution where as dual emission (excimer) in CD. Both drugs formed 1:2 (CD-drug(2)) inclusion complexes with CDs. Time-resolved fluorescence studies show that single exponential decay observed in water whereas biexponential decay observed in CD. Nano-sized particles were found in ISOP/CD while vesicles were obtained in MDOP/CD complexes. DSC results revealed that the thermal stability of drugs was improved when it was included in the CD nanocavity. Based on PM3 calculations, the inclusion structure of ISOP/CD and MDOP/CD complexes were proposed. Thermodynamic parameters and binding affinity of complexation of CD were determined by PM3 method. (C) 2013 Elsevier B.V. All rights reserved.